CN107635497B

CN107635497B - Optical tissue feedback device for electrosurgical devices

Info

Publication number: CN107635497B
Application number: CN201680026176.1A
Authority: CN
Inventors: W·C·J·比尔霍夫; B·H·W·亨德里克斯; F·M·A·M·范加尔; T·M·比德隆; V·V·普利; C·赖克
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2015-05-06
Filing date: 2016-04-26
Publication date: 2020-12-01
Anticipated expiration: 2036-04-26
Also published as: EP3291753A1; US11576717B2; US20180303539A1; CN107635497A; JP7057672B6; US20230149066A1; JP2018524030A; JP7057672B2; WO2016177600A1

Abstract

A tissue sensing device for use with an electrosurgical knife is presented, the tissue sensing device comprising a proximal portion, a distal portion, and a clamping portion between the proximal portion and the distal portion. The proximal end portion is configured for attachment to a housing of the electrosurgical knife. The distal end portion is configured to movably support a blade of the knife. A distal end of an optical fiber is arranged at the distal end portion of the device, and a proximal end of the optical fiber is connectable to an optical console, such that optical measurements can be performed at the distal end portion.

Description

Optical tissue feedback device for electrosurgical devices

Technical Field

The present invention generally relates to devices for tissue sensing and systems for electrosurgery including the devices. In particular, the present invention relates to a device for tissue sensing having an optical fiber, wherein the device is configured to be attached to an electrosurgical knife.

Background

In electrosurgery, a high frequency electrical current is applied to tissue in order to cut, coagulate, dry or cauterize the tissue. Such devices have been used in 80% or more of all surgical procedures, indicating the usefulness of the device. Depending on the tissue in front of the device, the surgeon can decide which mode of operation to use the device.

During breast tumor surgery (e.g., lumpectomy), the goal of the surgeon is to remove the breast tumor without leaving more than the lesion-positive margin, i.e., the surgeon wants to avoid leaving a substantial portion of the tumor, as this would result in recurrence of the tumor. The remaining minute portion can be treated by an additional radiotherapy treatment.

Although the surgeon can conceive images of the tumor from preoperative images (e.g., images taken during mammography), there is no feedback about the tumor during surgery. Due to the lack of such feedback during surgery, a large number of surgeries result in such positive margins and additional surgeries are required.

Various approaches have been proposed to provide feedback during surgery, for example, by performing pathological testing during surgery (e.g., cryo-section analysis or touch-prepared cytology). Another option is to use spectra to examine the excised sample. These options are cumbersome because when a positive edge is detected on the excised sample, it is difficult to find the exact location in the body where additional tissue must be excised due to the positivity.

In patent application WO 2013/108194, an electrosurgical knife incorporating optical tissue sensing is proposed. The problems not solved in this application are: for example, during a cutting procedure with an electrosurgical knife, debris may adhere to the blade, which may obscure optical tissue sensing.

In document US20070239033, a device for identifying characteristics of a blood vessel contained within a tissue is described. In such devices, a radiation source provides radiation to the tissue and a probe receives radiation back from the tissue. The data relating to the tissue is processed and used to indicate whether the blood vessel is near the tip of the probe. US2009/0275840 a1 discusses vascular sensing catheters.

There are many other surgical procedures in which it is also important to identify tissue, the breast example being merely an example. The importance of tissue discrimination is not limited to tumor surgery, but may also be necessary in orthopedic, neurological or cardiovascular surgery.

Disclosure of Invention

The general problem is to improve the optical sensing arrangement in electrosurgery in order to obtain more reliable measurements of tissue. This is achieved by the subject matter of the independent claims. Further embodiments are described in the dependent claims.

Another problem may be to provide a medical device with an electrosurgical tool with optical tissue feedback, which may be mounted on a blade of an electrosurgical knife, and which electrosurgical tool is configured to change its position such that it is at a proximal end portion of the blade during cutting and at a distal end side when optically sensing tissue.

To address these issues, the optical tissue sensing device may change the position of at least part of the device relative to the blade by pressing the lever so that the sensing portion is at the proximal portion of the blade during cutting and at the distal end when optically sensing tissue. The device may include a lever proximate to an activation button of the electrosurgical knife such that movement of the device can be activated proximate to the location. In the proximal position, no or at least less debris may reach the optical sensing element of the device during cutting, i.e. this prevents obscuring the optical measurement.

It should be understood that the use of a sensing device during the cutting process is also possible. In this case, the sensing console may be linked to the cutting console, such that the cutting process can be controlled by the sensing console. For example, the control can be established by making a connection between a plug of an electrosurgical knife and a socket of an electrical console.

Another way may be to generate a signal from an optical console during the cutting process, the signal indicating that the critical structure is nearby. The signal can be in any form, such as a visual signal, an audible signal, a vibration, an on-screen indication, and the like.

In general, a tissue sensing device for use with an electrosurgical knife includes a body and an optical fiber. The body may be in the form of a sleeve comprising a proximal portion, a distal portion and a gripping portion between the proximal and distal portions. The proximal portion (i.e. the portion closer to the operator of the device in use) is configured for attachment to the housing of the electrosurgical knife, for example by receiving a portion of the housing thereof. The distal end portion (i.e. the portion which, in use, is remote from the operator) is configured for movably supporting a blade of a knife. In other words, at least the distal end portion of the body is movable relative to and at the blade of the electrosurgical knife. A distal end of an optical fiber is arranged at the distal end portion of the body and a proximal end of the optical fiber is connectable to an optical console such that optical measurements can be performed at the distal end portion of the body, preferably at a front surface of the distal end portion of the body. Thus, the distal end of the optical fiber is positioned separate from the blade; i.e. the distal end of the optical fibre does not form part of the blade. In doing so, the cleaning or clearing cycles of these components can be independently determined; that is, the blade may be reused and the optical fiber may be a disposable component.

According to an embodiment, the tissue sensing device may further comprise a guide tube, wherein the optical fiber may be movably accommodated within the guide tube. When the fiber is not in use, the fiber may be retracted into the guide tube to protect the fiber end.

According to a further embodiment, the tissue sensing device may further comprise a protection plug, which may be arranged at the distal end of the optical fiber and which is configured to transmit light from and/or to the optical fiber. The protection plug may have a shape and may be arranged so as to act as a lens for the transmitted light. Furthermore, the protection plug may close any gaps at the guide tube to avoid any debris or tissue or liquid entering said gaps.

Further, the tissue sensing device may comprise a cleaning element configured to clean an end of the optical fiber as the optical fiber moves within the guide tube. For example, the cleaning element may be a brush or other element arranged in or at the guide tube such that the optical fibers may be in contact with the brush and may move along the brush.

According to an embodiment, the optical fiber is movable relative to the distal portion of the body such that a distal end of the optical fiber protrudes beyond the distal portion of the body. In this way, the front surface of the optical fiber can be brought into close contact with the tissue in front of the distal end portion of the main body.

The tissue sensing device may further comprise a fiber connector at the body for optically connecting the optical fiber with the optical console. In other words, additional fiber optic cables may be used to connect the optical fibers of the tissue sensing device with the optical console.

According to another embodiment, a system may be provided comprising the above-mentioned device and a console comprising a light source, a light detector and a processing unit for processing signals provided by the light detector, wherein one of the light source and the light detector may provide wavelength selectivity. The light source may be one of a laser, a light emitting diode, or a filtered light source, and the console may further include one of a fiber switch, a beam splitter, a grating, or a dichroic beam combiner. Furthermore, the device may be adapted to perform at least one of the group consisting of: diffuse reflectance spectroscopy, diffuse optical tomography, differential path length spectroscopy, fluorescence spectroscopy, and raman spectroscopy.

According to another aspect, a system is proposed having an electrosurgical knife and a tissue sensing device as described above. The blade may include a housing for attachment to the proximal end portion of the tissue sensing device and a blade configured to be movably supported by the distal end portion of the tissue sensing device.

The tissue sensing device and/or the electrosurgical knife may include a lever for moving the distal end portion of the tissue sensing device between a first position in which the distal end portion is positioned at an end portion of the blade and a second position in which the distal end portion is positioned adjacent the housing of the knife.

According to another embodiment, a resilient element may be provided for biasing the distal portion of the tissue sensing device in a direction toward the end portion of the blade.

According to a further embodiment, the clamping portion of the tissue sensing device may be configured to elastically deform to move the distal end portion relative to the blade of the knife.

Not only a cleaning element for cleaning the optical fiber but also a means for cleaning the blade of the knife can be provided. Means for cleaning the blade may be disposed at the distal end portion of the tissue sensing device for contact with the blade to clean the blade by moving the distal end portion of the tissue sensing device along the blade. The blade may alternatively or additionally be coated with a release layer.

The system may also include an electrical console for providing electrical current to the blade of the knife.

The aspects defined above and further aspects, features and advantages of the present invention can also be derived from the examples of embodiments described hereinafter and are explained with reference to the examples of embodiments. The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

Drawings

Fig. 1 is a schematic diagram of a system having a tissue sensing device in a first position relative to an electrosurgical knife.

Fig. 2 is a schematic diagram of a system having a tissue sensing device in a second position relative to an electrosurgical knife.

Fig. 3 illustrates an embodiment of a tissue sensing device having an electrosurgical knife.

FIG. 4 illustrates an embodiment of a tissue sensing device having two clamping portions in a first position relative to each other.

FIG. 5 illustrates an embodiment of a tissue sensing device having two clamping portions in a second position relative to each other.

Fig. 6 illustrates an embodiment of a device having an end portion for cleaning an optical fiber.

Fig. 7 illustrates an embodiment with a fiber connector.

FIG. 8 illustrates an embodiment having elements for biasing the tissue sensing device in a direction toward the distal end of the blade.

FIG. 9 is a schematic view of an additional embodiment of a tissue sensing device having an electrosurgical knife.

FIG. 10 is an illustration of the distal end portion of the blade and guide tube for the optical fiber and a detailed view of the guide tube.

Fig. 11 shows a system according to an embodiment and a log plot of absorption coefficients of blood, water and fat.

The illustrations in the figures are merely schematic and are not drawn to scale. It should be noted that where appropriate, similar elements in different drawings are provided with the same reference numerals.

List of reference numerals:

100 electric surgical knife

110 blade

120 optical fiber

130 casing

140 suction device

150 electric control desk

160 optical console

164 light source

166 photo detector

168 monitor

170 trigger/switch

180 connection

190 optical connector

195 control rod

200 tissue sensing device

210 optical cable

220. 240 elements of a tissue sensing device

223. 243 proximal end portion

224. 244 clamping portion

225. 245 distal portion

230 fiber outlet

250 cleaning element

260 elastic element

270 recess

280 guide tube

290 optical plug

Detailed Description

It is presented a tissue sensing device configured to be mechanically attached to an electrosurgical knife and capable of being in at least two positions: a proximal position and a distal position. The tissue sensing device further comprises at least one optical fiber, wherein a distal end of the optical fiber is located at an end of the device, the optical fiber being capable of transmitting and receiving light. The optical fiber may be connected to an optical console capable of transmitting and receiving light and capable of analyzing the received light. With this arrangement, the tissue type in front of the tissue sensing device can be determined and a signal dependent on the tissue type can be generated.

Additionally, a system is presented that includes an electrosurgical tool, such as a knife, connected to an electrical console, wherein the tool is capable of cutting, coagulating, drying, or burning tissue based on operation of the electrical console and a tissue sensing device attached to the tool.

Fig. 1 and 2 are schematic diagrams of a system including a tissue sensing device 200 and an electrosurgical knife 100 having a blade 110. The device 200 has two optical fibers 120. The optical fibers are connected to the optical console 160 by means of an optical connector 190 and an optical cable 210. The blade 110 is electrically connected to an electrical console 150, which electrical console 150 is capable of sending electrical signals to the blade to cause various treatments, such as cutting, coagulating, drying, or burning tissue. The blade is capable of performing these treatments on tissue in contact with the blade. One of the optical fibers 120 is connected to a light source in the optical console 160 that illuminates the tissue when in contact with the tissue sensing device 200. Scattered light that has passed through tissue in contact with the tissue sensing device is collected by the second optical fiber 120 and directed to the optical console 160. Here, the light is spectrally analyzed. From the spectral features, the tissue type in front of or directly adjacent to the blade can be determined. For example, the use of a white light source and the detection of diffusely reflected light enables the detection of the presence and concentration (e.g., water content and fat content) of various chromophores. Fluorescence detection can also be used to determine tissue composition.

Although fig. 1 and 2 show embodiments with two fibers, it is also possible to use only one or more than one fiber. For example, in the case of three fibers as shown in fig. 3, it is also possible to obtain directional information. For example, using the bottom fiber and the middle fiber as a source-detector pair and comparing it with the information of the middle fiber and the upper fiber as a source-detector pair, the signal difference provides information about the tissue difference in both directions.

A trigger or switch 170 may be provided at the housing 130 of the knife 100 to select different modes of operation depending on the signal displayed on the optical console 160. Optionally, there may be a feedback loop 180 that interferes with the mode of operation of the electrical console 150.

Further, the tissue sensing device 200 may have a lever 195 that is switchable from a first mode in which the device 200 is in a proximal position at the blade, as shown in fig. 1, to a second mode in which the device 200 is in a distal position, as shown in fig. 2. For example, in a first mode, the electrosurgical knife may be used for cutting, while in a second mode, the device is capable of performing tissue sensing. It is also possible to use the second mode during cutting. In this way, feedback information from the optical console can be used directly to interrupt the cut as the critical structure is approached.

In fig. 3-5, an embodiment is shown wherein the tissue sensing device comprises two

elements

220, 240, each element having a proximal end portion for attachment to the housing 120 of the electrosurgical knife and a

distal end portion

225, 245 for receiving the blade 110 of the knife. The tissue sensing device according to this embodiment can be positioned in three configurations. In a first configuration (see fig. 3), the tissue sensing device 200 is in a proximal position and the electrosurgical knife with its blade projecting distally from the tissue sensing device can be used in a standard manner. In configuration 2 shown in fig. 4, the tissue sensing device is advanced to the distal end portion of blade 110. Tissue sensing devices can now be used as probes to measure tissue in contact with and/or in front of the blade. In configuration 3 shown in fig. 5, the tissue sensing device is still at the end of blade 110, but first element 220 is moved relative to second element 240 such that fiber end 125 of optical fiber 120 now protrudes beyond distal end portion 225 of first element 220 of the tissue sensing device. Depending on the position of the tissue sensing device, the fiber end 125 may also protrude beyond the end of the blade. In this way, the fibers may be forced into intimate contact with the tissue in front of the blade. This allows the tissue to be cut to be measured and thus allows corrective action to be taken prior to cutting. This option allows depth measurements to be made at any depth, for example, when a sharp edge of a few millimeters is required and the probing depth of the source-detector fiber combination in configuration 2 is too shallow. It is also possible to use three fibers with different spacing distances between the fibers. Two fibers can have a short separation distance while another combination of two fibers has a larger separation distance. This can allow shallow and deep investigation of tissue and give a better indication of critical structures in front of the blade.

In an embodiment, the tissue sensing device may have a cleaning function such that debris present on the blade is removed when advanced toward the distal end of the blade. Various devices can be envisaged such as a plough used in farming. Further, the blade and/or the tissue sensing device can be coated with an anti-adhesion layer. The tissue sensing device may also be combined with a suction device.

In another embodiment, as shown in fig. 6, the optical fiber can be positioned inside an optical port having an exit near the end of the knife. It should be understood that such an optical port may be integrated, for example, in the distal portion 225 of the tissue sensing device. A small cleaning brush 250 can be mounted within the optical port such that when the optical fibers 120 extend to the outlet 230 of the port, the fibers are wiped (or cleaned) before coming into contact with tissue. Each time the fibers shrink and extend to the end of the knife, they are cleaned, thus preventing debris from adhering and interfering with the optical signal. Alternatively, a brush is not even required. The optical fibres can be stored inside the port and extended to the outlet when required.

Further, the tissue sensing device may be secured to the end of the electrosurgical knife prior to the start of the procedure. The optical fiber can end at an optical connector 190, which optical connector 190 can be a female connector as shown in fig. 7. The fiber optic cable 210 may then be inserted into a receptacle when optical sensing is desired. This gives the surgeon more freedom about the equipment and he/she does not have to handle extra cables at the surgical site.

As shown in the embodiment of fig. 8, a biasing element, such as a spring 260, may be disposed, for example, in a recess 270 between the element 220 and/or 240 of the tissue sensing device assembly sensing device and the housing 130 of the knife to bias the respective element in one of the distal or proximal positions. This may, for example, help to bring the mechanical part back to the proximal position automatically after bringing it to the distal end of the blade. Moreover, this arrangement can help to more easily clean the blade.

In another embodiment (fig. 9), the middle portion of at least one of the

elements

220 and 240 can be made semi-rigid, as indicated by the double arrow in the figure, which is capable of collapsing. This retracting movement can facilitate sliding of distal ends 225 and/or 245 over blade 110 of the knife. This can help the mechanical parts to move easily on the knife part. Moreover, this arrangement enables easy movement, facilitating easier cleaning of the blade.

In a further embodiment shown in fig. 10, the optical fiber can be positioned within a guide tube 280 that is mounted to the scalpel's blade 110. The guide tube exits adjacent the distal end of the blade. Within the tube 280, the movable optical fiber 120 can be positioned at the end with a small optical plug 290 comprising an optically transparent, non-absorbing, heat resistant material. In the detailed description of fig. 10A, 10B, and 10C, plugs having different shapes are depicted. The purpose of the plug 290 is to protect the fiber end 125 from direct contact with sparks and/or debris during the cleaving process. This is important because the fiber is composed of multiple layered components (core/cladding/protective buffer). Repeated movement of the fiber during use of the device may reduce the optical quality of the fiber, which can be prevented by sealing the fiber with such a protective optical plug, thereby providing optimal optical coupling from tissue to fiber and from fiber to tissue. This can be done by adding isotropic scattering particles to the optical material. This allows photons entering the plug material from any angle to be collected by the fiber. The plug material may be composed of a glue/resin that forms the solid termination of the fiber ends.

The plug may protrude slightly from the guide tube to reduce debris adhesion at the plug and further optimize light coupling towards the fiber. For example, the plug can be designed to have a smooth spherical shape, as shown in the detailed view of fig. 10B. The above solution provides additional protection for the retractable fiber end during operation of the device end to ensure that the fiber is free of debris when moving the fiber back to the distal end of the tube after cutting.

In addition, the plug may also provide sufficient protection for the fiber to allow continuous measurement throughout the procedure. In this case, the fibers need not even be movable and can be permanently fixed in their measuring position within the guide tube. For this fixed static solution, the optical plug can be designed in the following way: the termination point also smoothes the edges of the guide tube, as shown in the detailed view of FIG. 10C.

As shown in fig. 11, the optical fibers of the tissue sensing device at the electrosurgical device are connected to an optical console 160. An optical fiber can be understood as a light guide or an optical waveguide. In an embodiment, the console 160 includes a light source 164 and an optical detector 166, the light source 164 being in the form of a halogen broadband light source with an embedded shutter. The optical detector is capable of resolving light having the following wavelengths: the wavelengths of the light are substantially in the visible and infrared regions of the wavelength spectrum (e.g., 400nm to 1700 nm). The combination of light source 164 and detector 166 allows diffuse reflectance measurements. For a detailed discussion of diffuse reflectance measurements see "Estimation of lipid and water concentrations in scattering media with diffusion optical spectrum from 900 to 1600 nm" (j.biomed.opt.15, 037015, 2010), r.sachabe, b.w.hendriks, a.e.desjardins, m.van der vort, m.b.van der Mark, and h.j.c.m.sterenborg.

Optionally, the console can also be coupled to an imaging modality that can image the interior of the body, for example, when performing an ablation under image guidance. On the other hand, other optical methods can also be envisaged, such as extraction of tissue properties by diffuse optical tomography, differential path length spectroscopy, fluorescence spectroscopy and raman spectroscopy using multiple optical fibers.

Also shown in fig. 11 is an electrosurgical console 150 and suction device 140. The suction device may be connected to the electrosurgical device such that a negative pressure or vacuum can be applied to its distal end by the device.

The processor transforms the measured spectrum into a physiological parameter indicative of the tissue state and may visualize the result using monitor 168.

A computer program capable of running on a processor may be provided on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the internet or other wired or wireless telecommunication systems.

For fluorescence measurements, the optical console must be able to provide excitation light to at least one source fiber while tissue-generated fluorescence is detected by one or more detection fibers. The excitation light source may be a laser (e.g., a semiconductor laser), a Light Emitting Diode (LED), or a filtered light source (e.g., a filtered mercury lamp). Typically, the wavelength emitted by the excitation light source is shorter than the range of fluorescent wavelengths to be detected. Preferably, a detection filter is used to filter out the excitation light in order to avoid a possible overloading of the detector by the excitation light. When there are multiple fluorescent entities that need to be distinguished from each other, a wavelength selective detector, e.g., a spectrometer, is required.

In case fluorescence measurements are to be combined with diffuse reflectance measurements, excitation light for measuring fluorescence may be supplied to the same source fiber as light for diffuse reflectance. This can be achieved, for example, by using a fiber switch or a beam splitter with focusing optics or a dichroic beam combiner. Alternatively, separate fibers may be used to provide the fluorescence excitation light and the light for diffuse reflectance measurements.

To perform spectral inspection, a custom Matlab 7.9.0(Mathworks, Natick, MA) algorithm may be used to fit the acquired spectra. In this algorithm, a widely accepted analytical model was implemented, namely the model described by the references TJFarrel, MSPatterson and BCWilson "A differentiation of simulation solved, steady-state differentiation recovery for the non-innovative determination of tissue optical properties" (Med. Phys.19, 1992, page 879-888), the entire contents of which are incorporated herein by reference. The input parameter for the reference model is the absorption coefficient mu_a(lambda), reduced scattering coefficient mu'_s(lambda) and emitting and collecting fibers at the probe tipCenter-to-center distance therebetween.

In the following section, the model will be briefly explained. The formulas used are mainly based on the work of Nachabe et al, therefore reference is made to "Estimation of biological chromophoresis using differential optical spectroscopy" by R.Nachabe, B.H.W.Hendriks, M.van der Voort, AE and H.J.C.M.Sterenborg: the best of extension the UV-VIS wave range to include 1000to 1600nm "(Optics Express, Vol.18, 2010, page 1432-.

A double power law function can be used to describe the wavelength dependence of reduced scattering, where the wavelength λ is expressed in nm and normalized to a wavelength value λ ₀800 nm. The parameter a corresponds to the reduced scattering amplitude at that particular wavelength.

In this formula, the reduced scattering coefficient is expressed as the sum of mie scattering and rayleigh scattering, where ρ_MRIs the fraction of mie-ensemble reduced scatter. The reduced scattering slope of mie scattering is denoted b and is related to the particle size. For a uniformly distributed absorber, the overall light absorption coefficient μ_a(λ) can be calculated as the product of the volume fraction of the absorber and the extinction coefficient (see FIG. 7)

Instead of applying the absorption coefficient mu_a(λ) modeling as the sum of absorption coefficients weighted by the respective concentrations of the four chromophores of interest, the decision to groupThe tissue absorption coefficient is expressed as:

wherein the content of the first and second substances,

corresponds to the absorption of blood and

corresponding to the absorption of water and lipids together in the probed volume. Volume fractions of water and lipids are ν_WLIs [ lipid ]]+[H₂O]And v is_{Blood, blood-enriching agent and method for producing the same}Blood volume fraction representing the concentration of hemoglobin in 150mg/ml of whole blood.

The factor C is a wavelength-dependent correction factor that takes into account the influence of pigment packing and the change in shape of the absorption spectrum. This effect can be explained by the fact that: blood in tissue is limited to a very small fraction of the total volume (i.e., blood vessels). Red blood cells near the center of the blood vessel therefore absorb less light than those at the periphery. In fact, when uniformly distributed within the tissue, fewer red blood cells will produce the same uptake as the actual number of red blood cells distributed in the discrete blood vessels. The correction factor can be described as:

wherein R denotes the average vessel radius expressed in cm. The absorption coefficient associated with blood is given by

Wherein

And

respectively represent oxyhemoglobin HbO₂And an extinction coefficient spectrum of deoxygenated hemoglobin Hb. The oxyhemoglobin fraction of the total amount of hemoglobin was recorded as α_BL＝[HbO₂]/([HbO₂]+[Hb]) And is commonly referred to as blood oxygen saturation. The absorption due to the presence of water and lipids in the tested tissue is defined as:

in this case, the concentration of lipids in relation to the total concentration of lipids together with water can be written as α_WFIs [ lipid ]]/([ lipids)]+[H₂O]) Wherein [ lipids ]]And [ H₂O]Corresponding to the concentration of lipid (density 0.86g/ml) and water, respectively.

This way of correlating water and lipid parameters with the expression of absorption coefficients defined in equation 6, rather than estimating the water and lipid volume fractions separately, corresponds to a minimization of the covariance of the basis functions used for the fit, resulting in a more stable fit, see references r.chabe, b.h.w.hendriks, m.van der vort, AE, and h.j.c.m.stereosborg, "Estimation of biological phosphorous using differential optical spectroscopy: the best of extension the UV-VIS wall range to include 1000to 1600nm "(Optics Express, Vol.18, 2010, p.1432-. To further explain and verify this theorem, reference is made to: "optimization of lipid and water concentrations in scientific media with differential optical spectroscopy from 900 to 1600 nm" (J.biomed.Opti.15, 037015, 2010), R.H.W.Hendriks, A.E.Desjardins, M.van der Voort, MB van der Mark, and H.J.C.M.Sterenborg.

For example, optical tissue properties, such as scattering coefficients and absorption coefficients of different tissue chromophores (e.g., hemoglobin, oxygenated hemoglobin, water, fat, etc.) can be derived by means of the described algorithm. These properties differ between normal healthy tissue and diseased (cancerous) tissue.

The main absorbing components in normal tissue that absorb predominantly in the visible and near infrared light range are blood (i.e., hemoglobin), water, and fat. In the lower part of fig. 11, the absorption coefficient of these chromophores as a function of wavelength is presented. Note that blood absorption is dominant in the visible range, while water and fat absorption is dominant in the near infrared range.

One way to discern spectral differences is by principal component analysis. The method allows for classification of spectral differences, thereby allowing for tissue discrimination. In addition to diffuse reflectance, fluorescence can also be measured. Then parameters such as collagen, elastin, NADH and FAD can also be measured. In particular, the ratio NADH/FAD, referred to as the optical redox parameter, is of interest because it is an indicator of the metabolic state of tissue, as described in Zhang Q. et al, "tissue-free fluorescence spectroscopy of biological tissue" (Opt. Lett., 2000, Vol.25, No. 19, p.1451-1453), which is altered in cancer cells and is assumed to be altered when cancer cells are effectively treated.

It is also possible to detect the reaction of the body to exogenous fluorophores that can be detected by the tissue sensing device. Furthermore, these can also be correlated with the measurement results of exogenous fluorophores by imaging modalities like optical mammography based on diffuse optical imaging.

The physician can be provided with information about the progress and whether the area in contact with the interventional device is still safe for cutting in several ways. For example, a light indicator can be used which indicates that tumor tissue is still detected when red light is shown, and indicates that there is no tumor when green light is shown and/or optionally indicates that the system suspects a tumor when yellow light is shown.

Another way is to use a sound signal. Yet another way is to show the probability that a critical structure is in contact with the device, which can be shown as a bar on the display screen. Light indicators can also be incorporated on the scalpel itself so that the surgeon does not have to look at additional screens. A 2-color system can be used to indicate critical structures in the vicinity of the tissue sensing accessory.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. Although some measures are recited in mutually different dependent claims, this does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope.

Claims

1. A tissue sensing apparatus (200) for attachment to an electrosurgical knife (100), the tissue sensing apparatus comprising:

a body having a proximal end portion (223, 243) configured to receive a portion of a housing (130) of the electrosurgical knife and a distal end portion (225, 245) configured to movably support a blade (110) of the knife, and a clamping portion (224, 244) between the proximal end portion and the distal end portion, an

An optical fiber (120), wherein a distal end of the optical fiber is arranged at the distal end portion and a proximal end of the optical fiber is connectable to an optical console (160);

wherein the distal end of the optical fiber (120) is further arranged at the distal end portion (225, 245) such that when a blade (110) of the electrosurgical knife (100) is supported by the distal end portion (225, 245), the distal end of the optical fiber is positioned separate from the blade; and is

Wherein the distal end portion is movable relative to and at the blade of the electrosurgical knife.

2. The tissue sensing device of claim 1, further comprising a guide tube (280), wherein the optical fiber (120) is movably housed within the guide tube.

3. The tissue sensing device according to any one of the preceding claims, further comprising a protection plug (290) arranged at the distal end of the optical fiber (120) and configured to transmit light to/from the optical fiber.

4. The tissue sensing device of claim 2, further comprising a cleaning element (250) arranged and configured for cleaning an end of the optical fiber as the optical fiber moves within the guide tube (280).

5. The tissue sensing device of claim 1 or 2, wherein the optical fiber (120) is movable relative to the distal end portion (225, 245) such that the distal end of the optical fiber protrudes beyond the distal end portion.

6. The tissue sensing device of claim 1 or 2, further comprising a fiber connector (190) for optically connecting the optical fiber to an optical cable (210) for connecting the optical fiber (120) with the optical console (160).

7. The tissue sensing device of claim 1 or 2, further comprising an optical console (160) configured for tissue examination.

8. An electrosurgical knife (100) comprising the tissue sensing device (200) according to any one of the preceding claims, the knife comprising a housing (130) for attachment to the proximal end portion (223, 243) of the tissue sensing device and a blade (110) configured to be movably supported by the distal end portion (225, 245) of the tissue sensing device.

9. The electrosurgical knife of claim 8, further comprising a control lever (195) for moving the distal end portion of the tissue sensing device (200) between a first position in which the distal end portion is positioned at an end portion of the blade and a second position in which the distal end portion is positioned near the housing (130) of the knife.

10. The electrosurgical knife of claim 8 or 9, further comprising a resilient element (260) for biasing the distal end portion of the tissue sensing device in a direction toward the end portion of the blade (110).

11. The electrosurgical knife of any of claims 8 to 9, wherein the clamping portion (224, 244) is configured to elastically deform to move the distal end portion (225, 245) relative to the blade (110) of the knife.

12. Electrosurgical knife according to any one of claims 8 to 9, wherein means for cleaning the blade (110) of the knife are provided at the distal end portion of the tissue sensing device.

13. Electrosurgical knife according to any one of claims 8 to 9, wherein the blade (110) is coated with an anti-adhesive layer.

14. The electrosurgical knife of any of claims 8 to 9, further comprising an electrical console (150) for providing electrical current to the blade of the knife.